Apparatus for dispensing measured quantities of lubricant

ABSTRACT

A device for detecting undesired amounts of gas in a lubricant dispensing system includes a measuring chamber connected to a lubricant dispensing system and configured to receive lubricant therefrom, a moveable rod located at least partially inside the measuring chamber, an actuator operably connected to the measuring chamber and adapted to create at least a partial vacuum in the measuring chamber as the measuring chamber fills with lubricant, and a sensor for detecting a rate of compression or expansion indicative of undesired levels of gas in the lubricant by sensing movement of the moveable rod when the lubricant enters the measuring chamber. The device is constructed to dump charges of lubricant having unacceptable levels of entrapped air, and further includes an adjustment mechanism permitting adjustment without unnecessarily dumping lubricant in the measuring chamber.

BACKGROUND OF THE INVENTION

The present invention relates to lubricant dispensing systems, and moreparticularly to lubricant dispensing systems that detect gas in alubricant.

Excess air entrapped in grease can cause an improper amount of grease tobe deposited onto production parts or in other lubricant dispensingapplications. This is normally caused by incorrect grease handling,changing of the original grease container, or improper pump priming. Thetrapped air in grease is compressed to a relatively small volume by thegrease supply pressure, which can be as high as 3000 p.s.i., but the airexpands to its normal size as the grease is discharged onto theproduction part. The decompression of the air results in reduced amountsof grease on the production part where the grease should have been.Prior to the present invention, there was no known accurate method bywhich to detect and dispose of grease including unacceptable amounts ofentrapped air. This problem is particularly troublesome where thecharges of grease being deposited are relatively small. The lack of suchan accurate method has resulted in many "faults" on parts as far asgrease volume dispersion.

U.S. Pat. No. 4,993,516 to Taiani discloses an apparatus including apiston that separates a lubricant chamber and a gas chamber. If there isgas in the lubricant, the piston is moved and a relief valve is openedto allow the gas to escape through the piston and gas chamber. However,the Taiani invention does not provide an accurate way to detect aspecific untolerable amount of entrapped air in the lubricant, nor doesthe device of Taiani provide for means to dump the charge of lubricantwhen the charge has the undesired amount of entrapped gas.

Other patents such as U.S. Pat. No. 3,633,612 to Gross and U.S. Pat. No.4,520,902 to Snow teach sensing means for measuring pressuredifferential in a lubricant, but do not offer means for sensingundesired amounts of air in a lubricant.

Accordingly, there is a need in industry for a device that will senseundesired amounts of air in a charge of grease, and dump the charge ifit contains an untolerable or undesirable amount of air. Furthermore,there is a desire in industry to be able to easily adjust the size ofthe charge once it is in the device that measures excess air, withoutdischarging any of the grease first.

SUMMARY OF THE INVENTION

One aspect of the present invention is an apparatus for detectingundesired amounts of gas in lubricant in a lubricant dispensing systemcomprising a measuring chamber adapted for connection to a lubricantdispensing system and configured to receive lubricant therefrom, amoveable rod located at least partially inside the measuring chamber, adevice operably connected to the measuring chamber and configured tocreate a change in pressure on the lubricant in the measuring chamber,and a sensor configured to sense movement of the rod indicative ofundesired levels of gas in the lubricant.

Another aspect of the present invention is an apparatus for measuringundesired levels of gas in a lubricant comprising a measuring chamberadapted for connection to a lubricant dispensing system and configuredto receive lubricant therefrom, a moveable rod located at leastpartially inside the measuring chamber, an actuator operably connectedto the measuring chamber and constructed to create a change in pressureon the lubricant in the measuring chamber, a sensor configured to detectunacceptable rates of movement of the rod due to an undesirable level ofgas being present in the charge of lubricant by measuring the movementof the moveable rod when the charge of lubricant is undergoing thechange in pressure, a discharge valve connected to the measuring chamberby a lubricant line, and a discharge valve controller configured to openthe discharge valve when the sensor detects an unacceptable compressionrate in the charge of lubricant to thus dispose of the charge.

Still another aspect of the present invention is a lubricating systemcomprising a pressurized lubricant supply, a measuring chamberconfigured to receive lubricant from the pressurized lubricant supply,and a sensor detecting a rate of compression or expansion of thelubricant indicative of undesired levels of gas in the lubricant bysensing the rate of expansion or compression of the lubricant in themeasuring chamber.

Yet another aspect of the present invention is an apparatus fordetecting undesired amounts of air in lubricant in a lubricantdispensing system comprising a measuring chamber adapted for connectionto a lubricant dispensing system and configured to receive a charge oflubricant therefrom, a moveable rod located at least partially insidethe measuring chamber, a device operably connected to the measuringchamber and constructed to create a change in pressure in the measuringchamber on the charge of lubricant, a sensor for detecting undesiredlevels of air in the charge of lubricant in the measuring chamber, thesensor sensing movement of the moveable rod in response to the change inpressure causing an unacceptable change in volume of the discharge oflubricant indicative of excess internal air, a valve located downstreamfrom the measuring chamber, a valve controller constructed to close thevalve when the sensor senses an acceptable level of internal air,thereby allowing the lubricant charge to be dispensed onto a productionpart, and constructed to open the valve to allow the lubricant charge tobe discarded when the sensor senses an unacceptable level of air in thelubricant charge, and an adjuster operably connected to the measuringchamber for adjusting the volume of output of lubricant from themeasuring chamber.

Yet another aspect of the present invention is a method of detectingundesired amounts of gas in a lubricant comprising the steps ofproviding a device including a measuring chamber for holding a charge oflubricant, a moveable rod located at least partially inside themeasuring chamber, and a sensor for detecting an unacceptable rate ofcompression or expansion indicative of undesired levels of gas when thecharge of lubricant undergoes a change in pressure by measuring the rateof movement of the rod; accumulating lubricant in the measuring chamberto create a charge of lubricant; determining the rate of compression orexpansion of the charge of lubricant to determine if an undesirableamount of gas is present in the charge of lubricant; and selectivelydumping the charge of lubricant if there is an undesired amount of gasin the charge and discharging the charge of lubricant for use if thereis an acceptably limited amount of gas in the charge of lubricant.

These and other features, advantages and objects of the presentinvention will be further understood and appreciated by those skilled inthe art by reference to the following specification, claims and appendeddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a device for measuring undesired amounts of gasin a lubricant according to the present invention;

FIG. 2 is a plan view of the measuring system of the device of thepresent invention;

FIG. 3 is a schematic of a lubricant dispensing system according to thepresent invention with the measuring chamber in the unfilled state;

FIG. 4 is a schematic of a lubricant dispensing system according to thepresent invention with the measuring chamber in the filled state;

FIG. 5 is a schematic of a lubricant dispensing system of a presentinvention with the measuring chamber in the compressed state; and

FIG. 6 is a logic diagram of the steps of the gas compressibility testof the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

The grease measuring system (FIG. 1) of the present invention generallyincludes a lubricant dispensing system 5, a grease inlet 10, a measuringchamber 12, sensors 14, 16, and 18 connected by wires 14', 16', and 18'to programmable controller PLC, a grease dump line 20, a greasedischarge line 22, and a housing 24.

Grease inlet 10 is a standard grease line from a central pump (notshown), with grease pressures preferably being between about 800 p.s.i.and about 2500 p.s.i. However, the grease line pressure may be as highas 3000 p.s.i. Located on grease inlet 10 is a restrictor 30, which isneeded to slow grease flow as it travels from the grease supply into themeasuring chamber 12. The restrictor 30 allows the present system totemporarily draw a partial vacuum in the measuring chamber, whichresults in detectable increased rates of expansion if the grease hasentrapped air. Grease inlet 10 is connected to a two-way grease inletvalve 32 which opens to allow grease to enter the measuring chamber 12through grease line 34, which is connected to measuring chamber 12 atone end.

FIG. 2 shows a more detailed view of the inner workings of the greasemeasuring system, including measuring chamber 12. Measuring chamber 12has an adjustable volume chamber 40. In the illustrated system, themeasuring chamber can hold from about 0.1 cc to about 4.6 cc oflubricant, although larger or smaller chambers are contemplated. Insidethe adjustable volume chamber 40, at the end of the measuring chamber 12opposite the grease line 34, is a moveable rod 42. The rod 42 ispartially inside the adjustable volume chamber 40 and partially outsideof it. Moveable rod 42 is preferably about 7/16 ths of an inch indiameter and has a 2-inch stroke inside the adjustable volume chamber40. The moveable rod 42 is held in place in measuring chamber 12 bysealed O-rings (not shown). An adjustment knob 44 is connected to themeasuring chamber 12 at its rod end by a threaded portion 46 whichallows the adjustment of the size of lubricant discharge from themeasuring chamber 12. The moveable rod 42 is in turn connected to acoupler 48. In operation, as discussed below, coupler 48 triggers one ormore of the three sensors of the device.

The first sensor, the "chamber-filled" sensor 14, is triggered when themeasuring chamber is filled with a charge of lubricant. The secondsensor, the "compressibility proximity" sensor 16, is triggered when anundesirable amount of air is present in the charge of lubricant afterthe lubricant charge is compressed. The third sensor, a "discharge"sensor 18, is triggered after the device has gone through a compressioncycle and results in discharge of the charge of lubricant from themeasuring chamber 12. The moveable rod 42 is attached to an air cylinder50, which houses the majority of the moveable rod 42 (see FIG. 3). Theair cylinder 50, in conjunction with the moveable rod 42 and restrictor30, allows a partial vacuum to be applied to the measuring chamber 12 asit is being filled with lubricant and further allows discharge of thelubricant from the measuring chamber 12 when the compression test iscomplete. An air logic valve 52 is positioned adjacent to the coupler 48to ensure that if air is present in the lubricant charge, the inlet willbe shut off. If such a valve is not present, the air entrapped in alubricant will get recompressed, which is undesirable.

The present invention apparatus also includes a discharge valve 60 whichis connected to the grease line 34, to the grease dump 20, and to thegrease discharge line 22. The discharge valve 60, as discussed below, isopened to allow grease to go to the grease dump 20 when the chargecontains an undesirable amount of air and opens to allow the grease tobe discharged to a nozzle or production part through the greasedischarge line 22 when the charge contains an acceptably low amount ofair.

As shown in FIG. 3, a compressed air line 70 supplies pneumatic pressureto various points of the grease measuring and dispensing system toperform various functions. The compressed air line 70 should preferablybe a minimum of 60 p.s.i. to ensure proper functioning of the system.The compressed air line 70 is operably connected individually topneumatic valves 72, 74, 76, 78, and 80. Each of the valves includes acontrol solenoid, designated A, B, C, D, and E, attached by wires, A',B', C', D' and E', respectively, to controller PLC. Solenoid A via anair line 73 is connected to valve 82, which in turn is connected totwo-way valve 32 via an air line 75. Solenoid B is connected to the aircylinder 56 via an air line 77, and solenoid C 76 is connected to theair cylinder 56 via an air line 79. Solenoid D 78 is connected to valve60 which is connected to the grease discharge line 22 and grease dump20. A programmable logic controller (PLC) (not shown) is used to controlthe activation and deactivation of the solenoids.

Other optional components of the grease measuring and dispensing systemare a strainer 90 (FIGS. 3-5) on the grease inlet 10 and a ball shutoffvalve 92 on the grease inlet 10 upstream from the restrictor 30 and thestrainer 90 to shut off the flow of lubricant to the system.

Operation

In operation, solenoid B 74 is energized to cause pneumatic pressure tobe applied to the end air cylinder 50. This pressure will be enough tobalance the friction of the seals of the air cylinder 50 and themeasuring chamber 12, and also to pull at least a partial vacuum in themeasuring chamber 12 as lubricant enters the measuring chamber. SolenoidA is then energized to activate valve A and supply pneumatic pressure tothe actuating port of the two-way grease inlet valve 32. This allows alubricant, such as grease, to flow from the grease inlet 10, through thetwo-way grease inlet valve 32, through the grease line 34, and to themeasuring chamber 12 until adjustable volume chamber 40 is filled. Asthe adjustable volume chamber 40 fills, the moveable rod 42 is moved inthe direction of the rod end of measuring chamber 12. The vacuumpreviously applied to the measuring chamber 12 will enlarge any airbubbles in the grease, due to the action of restrictor 30, making thefilled sensor 14 operate sooner than it would have if there were no airin the grease.

FIG. 4 shows the system in the filled position, that is, when theadjustable volume chamber 40 is filled with lubricant. At this point,the filled sensor 14 is actuated by coupler 48, which is positioned bymoveable rod 42 moving in the direction of the rod end of measuringchamber 12 when the chamber is filled with lubricant, causing the greaseinlet valve 32 to close. The filled sensor 14 will send an output signalto the user's PLC, indicating that the fill operation is complete. Airlogic valve 52 ensures that the inlet shuts off when the coupler reachesthe position of filled sensor 14. The timing of this action is criticalbecause continuing the grease input after the mechanism indicates thatit is filled will compress the air in the grease, making it impossiblefor the air to be compressed by the 12:1 boost ratio of the moveable rod42 to cause the movement necessary to recognize the presence of air.

Solenoid A of valve 72 and solenoid B of valve 74 is then deactivated bythe user's PLC, and solenoid C of valve 76 is also activated, causingthe air cylinder 50 to actuate the moveable rod 42, pressurizing thematerial in the measuring chamber 12. If the measuring chamber 12 hasbeen filled with compressible materials such as a combination of greaseand air, and if that compressible air is more than the allowable amount,the moveable rod 42 will quickly move and coupler 48 will actuate thecompressibility proximity sensor 16 as shown in FIG. 5. The location ofthe compressibility sensor 16 can be adjusted by the user to meet thegrease-to-air tolerance limits desired by the user. If after about ahalf a second, the moveable rod 42 does not move far enough to actuatethe compressibility sensor 16, the system has detected that themeasuring chamber 12 has been filled with a charge of lubricant thatdoes not contain a nontolerable amount of air and this grease can thenbe dispensed into the proper output device in the lubricant dispensingsystem 5, which is usually either a nozzle or a production part. Thecompressibility sensor 16 could also possibly be a linear digitalencoder and the PLC could use the "count" for a math equation to measurethe movement as a percentage of the amount of grease to be dispensed.

If the charge is a "good" charge, that is, it does not contain anundesirable amount of air, solenoid C 76 is left energized to pressurizethe material in the chamber, while solenoid D 78 is energized to supplyair pressure to the actuating part of the normally closed dispense valve60. This action will immediately allow the contents of the measuringchamber 12 to be dispensed back to the lubricant dispensing system 5 andthrough grease discharge line 22. The discharge sensor 18 will then beactuated. The customer's PLC should be programmed to monitor thedispense time to confirm that the dispensed charge is within the desiredlimits.

If the lubricant charge is "out of tolerance", that is, it contains anundesirable amount of air, the grease should not be used and should bediscarded. To dump the grease, valve 60 is opened and solenoid E ofvalve 80 causes the material to be pressurized in the measuring chamber12. This will immediately cause the contents of the measuring chamber 12to be dumped through grease dump line 20 and the discharge sensor 18 tobe actuated to indicate that the dump has been completed. The dump valvecan be manually operated or air pilot operated to allow the customer'sPLC to automatically dump the charge of lubricant.

Once discharge sensor 18 is activated, the system resets itself and isready for another measuring cycle. The system will then go throughprocess as described above for as many charges of grease as desired.Furthermore, if the compression test fails, the unit will default to thefail mode and then reset itself. Any type of sensor may be used for thefilled 14, compressibility 16, and discharge 18 sensors. Examples ofsuch sensors are mechanical, encoder, laser and optical sensors.

Another unique feature of the present invention is that the volume ofdischarge out of the measuring chamber 12 can be manually adjusted byusing adjustment knob 44 even when the measuring chamber 12 is filledwith a charge. The size of the charge can be adjusted by manuallyturning the adjustment knob 44 or by means of automatically adjustingthe output by using a servo motor. There is no loss of grease whilemaking such an adjustment and no grease has to be discharged frommeasuring chamber 12 for the adjustment to be made.

The above-noted sequence of steps is presented in sequential formdiagrammatically in FIG. 6. FIG. 6 shows the logic employed during thecompressibility test of the present invention from the beginning of thetest to the reset of the system. It is contemplated that either thecompressibility or the expandability of lubricant can be measured sinceentrapped air affects both. Accordingly, it is contemplated that thepresent invention includes measuring either expansion or compression oflubricant during a pressure change, and dumping the charge of lubricantif too much entrapped air is found therein.

The above description is considered that of the preferred embodimentonly. Modifications of the invention will occur to those skilled in theart and to those who make or use the invention. Therefore, it isunderstood that the embodiment shown in the drawings and described aboveis merely for illustrative purposes and not intended to limit the scopeof the invention, which is defmed by the following claims as interpretedaccording to the principles of patent law, including the doctrine ofequivalents.

What is claimed is:
 1. An apparatus for detecting undesired amounts ofgas in lubricant in a lubricant dispensing system comprising:a measuringchamber adapted for connection to a lubricant dispensing system andconfigured to receive lubricant therefrom; a moveable rod located atleast partially inside the measuring chamber; a device connected to themeasuring chamber and configured to create a change in pressure on thelubricant in the measuring chamber; a valve in communication with themoveable rod, the valve configured to cause an inlet valve to close; anda sensor configured to sense movement of the rod indicative of undesiredlevels of gas in the lubricant.
 2. The apparatus defined in claim 1wherein the device creates a partial vacuum in the measuring chamber. 3.The apparatus defined in claim 1 wherein the device includes anactuator.
 4. The apparatus defined in claim 3 wherein the actuator isoperably connected to a programmable logic controller.
 5. The apparatusdefined in claim 4 wherein the actuator includes a pneumatic cylinderconnected to the rod for compressing the lubricant and for transportingthe lubricant out of the measuring chamber.
 6. The apparatus defined inclaim 5 wherein the measuring chamber has a volume of about 0.1 cc toabout 4.6 cc.
 7. The apparatus defined in claim 6 including lubricant inthe measuring chamber at a pressure of between about 800 p.s.i. andabout 2500 p.s.i.
 8. The apparatus defined in claim 1 wherein themeasuring chamber has a volume of about 0.1 cc to about 4.6 cc oflubricant.
 9. The apparatus defmed in claim 1 including a lubricantsupply line filled with pressurized lubricant, and wherein when thelubricant is in the measuring chamber, the pressurized lubricant is at alower pressure than the pressurized lubricant.
 10. The apparatus definedin claim 1 including a pneumatic device attached to the rod formotivating the lubricant back into the lubricant dispensing system. 11.The apparatus defined in claim 1 including a discharger connected to themeasuring chamber and configured to discharge any lubricant having anunacceptable amount of gas therein.
 12. The apparatus defined in claim 1wherein the lubricant is grease.
 13. An apparatus for measuringundesired levels of gas in a lubricanta measuring chamber adapted forconnection to a lubricant dispensing and configured to receive a chargeof lubricant therefrom; a moveable rod located at least partially insidethe measuring chamber; an actuator operably connected to the measuringchamber and constructed to create a change in pressure on the charge oflubricant in the measuring chamber; a sensor configured to detectunacceptable rates of movement of the rod due to an undesirable level ofgas being present in the charge of lubricant by measuring the movementof the moveable rod when the charge of lubricant is undergoing thechange in pressure; a discharge valve connected to the measuring chamberby a lubricant line; and a discharge valve controller configured to openthe discharge valve when the sensor detects an unacceptable rate ofmovement of the rod to thus dispose of the charge.
 14. The apparatusdefined in claim 13 wherein the actuator is controlled by a programmablelogic controller.
 15. The apparatus defined in claim 14 wherein theactuator includes a pneumatic cylinder connected to the rod forcompressing the charge of lubricant and for transporting the lubricantout of the measuring chamber.
 16. The apparatus defined in claim 15wherein the measuring chamber has a capacity of about 0.1 cc to about4.6 cc.
 17. The apparatus defined in claim 16 including lubricant in themeasuring chamber at a pressure of between about 800 p.s.i. and about2500 p.s.i.
 18. The apparatus defmed in claim 13 wherein the measuringchamber has an inner volume capacity of from about 0.1 to about 4.6 ccof lubricant.
 19. The apparatus defined in claim 13 including alubricant supply line filled with pressurized lubricant therein, andwherein when the lubricant is in the measuring chamber, the pressurizedlubricant is at a lower pressure than the pressurized lubricant.
 20. Theapparatus defined in claim 13 including a pneumatic device attached tothe rod for motivating the lubricant back into the lubricant dispensingsystem.
 21. The apparatus defined in claim 13 including a pneumaticdischarger to discharge the lubricant for use upon completion of acompression test of the lubricant.
 22. The apparatus defined in claim 13wherein the lubricant is grease.
 23. A lubricating system comprising:apressurized lubricant supply; a measuring chamber configured to receivelubricant from the pressurized lubricant supply; and a sensor detectinga rate of compression or expansion of the lubricant indicative ofundesired levels of gas in the lubricant by sensing the rate ofcompression or expansion of the lubricant in the measuring chamber. 24.A lubricating system defmed in claim 23 including an adjusting meansoperably connected to the measuring chamber for adjusting a volumeoutput of the measuring chamber without discharging any lubricant fromthe measuring chamber even when the measuring chamber contains a fullcharge of lubricant.
 25. The lubricating system of claim 24 including anactuator which is controlled by a programmable logic controller.
 26. Thelubricating system of claim 25 wherein the actuator includes a pneumaticcylinder connected to a rod for compressing the charge of lubricant andfor transporting the lubricant out of the measuring chamber.
 27. Thelubricating system of claim 26 wherein the measuring chamber has acapacity of about 0.1 cc to about 4.6 cc.
 28. The lubricating system ofclaim 27 including lubricant in the measuring chamber at a pressure ofbetween about 800 p.s.i. and about 2500 p.s.i.
 29. The lubricatingsystem of claim 23 wherein the measuring chamber has an inner volumecapacity of from about 0.1 cc to about 4.6 cc of lubricant.
 30. Thelubricating system of claim 23 wherein the lubricant in the measuringchamber is at a lower pressure than the pressurized lubricant.
 31. Thelubricating system of claim 23 including a pneumatic device attached toa rod for motivating the lubricant back into the lubricant dispensingsystem.
 32. The lubricating system of claim 23, including a pneumaticdischarger to discharge the lubricant for use upon completion of acompression test of the lubricant.
 33. The lubricating system of claim23 including a line connecting the pressurized lubricant supply and themeasuring chamber, the line restricting flow of the lubricant into themeasuring chamber sufficiently to allow a pressure drop in the lubricantsufficient to cause a detectible amount of expansion of entrapped air.34. An apparatus for detecting undesired amounts of air in lubricant ina lubricant dispensing system comprising:a measuring chamber adapted forconnection to a lubricant dispensing system and configured to receive acharge of lubricant therefrom; a moveable rod located at least partiallyinside the measuring chamber; a device operably connected to themeasuring chamber and constructed to create a change in pressure in themeasuring chamber on the charge of lubricant; a sensor for detectingundesired levels of air in the charge of lubricant in the measuringchamber, the sensor sensing movement of the moveable rod in response tothe change in pressure causing an unacceptable change in volume of thecharge of lubricant indicative of excess internal air; a valve locateddownstream from the measuring chamber; a valve controller constructed toclose the valve when the sensor senses an acceptable level of internalair, thereby allowing the lubricant charge to be dispensed onto aproduction part, and constructed to open the valve to allow thelubricant charge to be discarded when the sensor senses an unacceptablelevel of air in the lubricant charge; and an adjuster operably connectedto the measuring chamber for adjusting the volume of output of lubricantfrom the measuring chamber.
 35. A method of detecting undesired amountsof gas in a lubricant comprising the steps of:providing a deviceincluding a measuring chamber for holding a charge of lubricant, amoveable rod located at least partially inside the measuring chamber,and a sensor connected to the rod for detecting an unacceptable rate ofcompression or expansion indicative of undesired levels of gas when thecharge of lubricant undergoes a change in pressure by measuring the rateof movement of the rod; accumulating lubricant in the measuring chamberto create a charge of lubricant; determining the rate of compression orexpansion of the charge of lubricant to determine if an undesirableamount of gas is present in the charge of lubricant; and selectivelydumping the charge of lubricant if there is an undesired amount of gasin the charge and discharging the charge of lubricant for use if thereis an acceptably limited amount of gas in the charge of lubricant.